Basic personality dimensions thought to underlie common forms of
child psychopathology are of interest in cognitive-behaviour therapy if
related to reinforcement contingencies used in treatment. Reward
dominance, or the tendency to be overly influenced by past experience of
reward, is one such response style. To obtain cross-national information
on this phenomenon, 136 New Zealand boys (aged 6 and 7) were
administered a version of the Miami Door Opening Task and rated for
conduct problems by parents and teachers. Half the boys were also given
a brief cognitive intervention designed to encourage an adaptive,
self-regulatory strategy that could have improved performance. Compared
to a neutral intervention, however, this manipulation did not influence
performance on the task. The majority of the participants tended towards
a reward-dominant response style, demonstrating that inhibiting a
previously rewarded behaviour in order to maximise a score is not
typical for boys of this age. However, the 10% of boys who met clinical
criteria for conduct disorder, but who had not been clinically referred,
did all score in the most reward dominant category.

**********

There has been considerable interest in developmental
psychopathology over the phenomenon of reward dominance in children and
its relationship to conduct disorder and antisocial behaviour. A major
impetus for this research has been evidence of continuity between
externalising problems in young children and antisocial activities in
adolescents (e.g., Fergusson & Horwood, 1996; Loeber, 1990;
Patterson, Reid, & Dishion, 1992). This progression indicates that
very basic dimensions of personality may be implicated in children who
are "early starters" with difficult temperaments,
distractibility, and oppositional characteristics. Moffitt (1993)
suggested these difficulties were linked to neurological deficits in
verbal regulation of behaviour and in executive functioning.

Lynam (1996) has proposed that children with this combination of
conduct and attentional symptoms have a deficit in personal constraint,
related to a reward-dominant response style. Broadly speaking, reward
dominance refers to the tendency to engage persistently in previously
reinforced behaviour, even when it is no longer adaptive to do so
(Newman, Patterson, & Kosson, 1987). The term "dominance"
implies that the tendency to continue behaviour that is rewarded is
greater than the tendency to cease (or inhibit) behaviour that is
punished. This is not the same as delay of gratification (Rachlin &
Green, 1972), which involves selecting a larger, more distant
reinforcement over a smaller but more immediate one.

Eysenck (1964) was the earliest theorist to suggest that delinquent
or psychopathic individuals have difficulty inhibiting previously
rewarded behaviour. Gray (1982) extended this model, noting that there
are two major motivational systems in the brain: the dopaminergic or
activating system that processes information about reward, and the
seretonergic or inhibiting system that is responsive to novel cues from
the environment and stimuli associated with past punishment. It was
argued that individuals with a dominant inhibitory system are anxiety
prone, and those with a dominant activation system are reward focused.
In two British studies, Fonseca and Yule (1995) confirmed that severely
conduct disordered and delinquent children were more sensitive to reward
than were a normative sample.

A modification of Gray's theory has been articulated by Quay
(1988). According to this model, conduct disorder involves a behavioural
activation system that dominates the inhibition system, whereas a
depressed inhibition system is thought to underlie attention deficits.
Shapiro, Quay, Hogan, and Schwartz (1988) tested these assumptions with
a card-playing task, involving both reward and punishment. Children
diagnosed as conduct disordered played significantly more cards. In a
subsequent study, Daugherty and Quay (1991) examined reward dominance in
children diagnosed according to various categories: conduct disorder,
attention-deficit/hyperactivity disorder (ADHD), both conduct disorder
and ADHD, and anxiety-withdrawal. They devised a computer game in which
the probability of opening a winning door decreased with each succeeding
set of doors. Participants could exchange points gained in the game for
a range of prizes that required higher points for the most desired
prizes. Children in both the conduct disorder and the conduct
disorder/ADHD groups persevered with the game, even when the probability
of winning a satisfactory prize was decreasing.

Many variables influence performance on tasks supposedly reflecting
reward dominance. Fonseca and Yule (1995) found that reward dominance
declined with age. Berman (1973) proposed that antisocial individuals
performed on reward-dominance tasks in a similar fashion to younger
children, persevering even when the odds were stacked against them.
Anxiety has been found to influence the number of doors opened
(O'Brien, Frick, & Lyman, 1994), such that boys with disruptive
behaviour disorders showed reward dominance only when anxiety was
controlled. O'Brien and Frick (1996) confirmed that children with
an anxiety disorder opened significantly fewer doors. Conversely, those
children who were most reward dominant were those with psychopathic
traits and no anxiety.

An issue that has not yet been addressed in the literature is the
possible relationship between characteristics believed to underlie
conduct disorder and the clinical interventions commonly used to modify
inappropriate behaviour (cf. Dumas, 1989; 1992). In this context, basic
personality characteristics have relevance for clinical assessment and
treatment design, with teaching children to attend to relevant cues and
to inhibit their behaviour representing a major approach to clinical
treatment (Kendall & Panichelli-Mindel, 1995). Training in
problem-solving skills is an effective method of reducing conduct
problems, often involving games, stories, and academic tasks (Kazdin,
1993). However, the focus has been on impulsivity, where the child seems
motivated by potential reward rather than attending to the most salient
environmental cue. Since a diversity of cognitive skills is typically
taught in any treatment program (Curtis, Ronan, Heiblum, Reid, &
Harris, 2002, this series), it is not known whether any of them
influence characteristics fundamental to conduct disorder, or instead
modify the inappropriate behaviours directly. Thus, it is of practical
as well as theoretical importance to determine if a reward-dominant
style is readily modifiable by a typical cognitive/ behavioural
intervention.

Method

Participants

The participants were 136 boys between the ages of six (N = 81) and
seven (N = 55) years who were enrolled in primary schools. Eight schools
agreed to take part, representing a diversity of geographic locations
and neighbourhoods of different socioeconomic conditions in the city of
Hamilton, New Zealand. The schools distributed information about the
study to parents of boys in the desired age range. Parents signed and
returned the informed consent letter and completed a Child Behavior
Checklist (CBCL). (The boys were also told later that they could stop
the study any time, or decide not to participate at all; neither event
occurred for any participant.)

Materials

Miami Door Opening Task. Daugherty and Quay (1991) developed this
task, based on a strategy utilised by Newman et al. (1987) to
investigate response perseveration in adult psychopaths. Our version of
the computer game consisted of a series of 100 door icons that were
presented one at a time in a pre-programmed order of winning and losing
doors. The child's task was simply to click on the door, at which
point it would open to reveal either a happy face (one point gain) or a
sad face (one point loss). To prevent the child from simply responding
continuously, or impulsively, there was a 3-sec. delay between
responding and the presentation of the next door (O'Brien et al.,
1994). The game was programmed on an IBM-type laptop computer that
automatically recorded the number of doors opened as well as the final
number of points scored.

Within the 10 series of 10 presentations, winning and losing doors
appeared randomly; however for each set of 10 the probability of winning
decreased by 10%. The total points earned were shown continuously at the
bottom right-hand corner of the screen, providing the child with a
running score of gains and losses, commencing with an initial
"gift" of 10 points. Effectively the child could earn until
about 35 points were showing on the screen, and then he started to lose
more than he had earned, until after 100 doors had been opened the child
would have no points. The adaptive behaviour in this game is to
"stop while you are ahead." The children had the task
explained to them and were then taken through a "trial" where
they used the computer controls and were shown the potential prizes to
be gained. The four prize boxes were displayed next to the computer, all
labelled with the required points that were necessary to take a prize
from them.

Teacher ratings of child's behaviour. Teachers were asked to
provide a global rating of each boy in terms of how well he fitted a
description of disruptive behaviour disorder. This description was a
composite of the symptoms listed in DSMIV (American Psychiatric
Association, 1994) for conduct disorder and oppositional defiant
disorder. The degree to which each boy exhibited the behaviours in the
vignette was rated on a 5-point Likert scale from "all the
time" to "never."

Child Behaviour Checklist (CBCL), ages 4-18, parent version
(Achenbach, 1991). The manual provides extensive reliability and
validity data for the CBCL, and a large sample, mixed according to
socio-economic status and ethnicity, provided US norms for boys aged
6-11 for the social competency and problem scales (Achenbach, 1991);
there are, however, no New Zealand norms currently available. A study by
Verhulst, Koot, and Van der Ende (1994) investigated the predictive
value of the checklist in a sample of 946 children aged 4 to 11, and
found that it was a good predictor of later behaviour problems. It was
necessary to modify the instrument slightly for the purpose of this
study. We removed all items related to medical conditions, since these
were not relevant to this investigation, as well as certain items that
are unlikely in a group of non-clinical children of this age (drug and
alcohol use, talk of killing self, hearing sounds and voices that
aren't there).

Cognitive intervention and control stories. Two stories were
developed, one as a cognitive intervention ("Fred the Kiwi's
Worm Hunting Trip") and one as a control ("Fred the Kiwi Goes
Hunting"). Both stories were approximately 700 words long, in
language suitable for children of this age. The stories were recorded on
audiotape and played to the participants, accompanied by lively coloured
illustrations.

The cognitive intervention story was based on standard
metacognitive procedures, modelling a verbal strategy for overcoming
reward dominance. The story's character, Fred the Kiwi, was shown
focused on gaining as many rewards (worms) as possible. Consequently, he
failed to notice the sun coming up and was forced to flee home leaving
his food reward behind. Fred was then shown learning from this
experience and putting the lesson into practice when he went hunting the
next night (i.e., "I am not going to make the same mistake again of
thinking only of how many worms I can catch. Instead I will stop and
think about how I am doing.") Fred would stop every so often and
look around, noticing the dawn approaching, and thus had time to take
the worms he had captured home to eat. The story reflected an adaptive
approach of stopping, thinking, and attending to changes in competing
contingencies.

The control story featured the same character, Fred the Kiwi, going
worm hunting. It utilized the same illustrations, but there was no
cognitive strategy embedded in the text. While the story was
interesting, it was a narrative only, containing no messages or morals.
Pilot testing of the stories showed that boys of this age could explain
the principles of the lesson to be learned from the first story. However
in this particular study there was no explicit instruction to link the
moral of the story with the subsequent computer game.

Procedure

A female research assistant collected participants, one at a time,
from their classroom, during regular school hours, and ensured that they
felt comfortable with the procedure. The participants were tested in a
quiet room provided by each school, by one of the authors, with the
research assistant present. After the child gave additional verbal
consent to proceed, he was randomly assigned to one of the two story
conditions. The story was played on audiotape and lasted five minutes.
During the story, the child was shown colour pictures to illustrate
various scenes.

Immediately after listening to the story, the computer task was
introduced. First the boys were shown the four open prize boxes. Printed
on the outside of each box was the range of game points required to earn
a toy from that box (Box 1, 0- 15 points; Box 2, 16-25; Box 3, 26-33;
and Box 4, 34-40). The lowest point level box, Box 1, contained only
stickers, while Box 4 contained the most attractive prizes, such as
model cars and other expensive items that we knew to be highly desirable
to boys of this age. This was designed to motivate participants to aim
for the top prizes. Participants were clearly told they could stop at
any stage of the game and exchange the points they had obtained for a
prize.

After being shown the prizes, participants received standard
instructions on how to play the game. They were also given a
demonstration of clicking the cursor on the door icons and the
consequence of finding a happy or sad face behind these. After telling
the researchers when they were ready to stop (or when they had opened
100 doors and the game was over), the boys were allowed to exchange
their game points for a prize. They were then taken back to their
classroom.

Results

Behaviour During the Task

Detailed notes on the behaviour of the children were kept by the
research assistant. All the boys seemed interested in the game and
typically smiled when they scored a point (opened a door to a happy
face) and grimaced when they lost a point. Many counted their points out
loud until their score was about 20, at which time the number of losing
doors increased and the children concentrated more on the computer task.
Comments of dismay increased after a number of lost points. Only a few
boys overtly verbalized a self-imposed rule, such as "I will stop
at 30 points" or "I will stop if I get another losing
door," but tended to be successful when they did so. After a string
of losing doors, superstitious behaviours were noticed, such as
switching hands on the computer mouse, or looking away from the screen.
At the end of the game, some participants said that they would play
differently next time. Many said they would be willing to play the game
again, even though they failed to gain a desirable prize.

Distribution of Number of Doors Opened

The distribution of scores (not points obtained by each child, but
the number of doors opened) is depicted in Figure 1. It will be noted
that the modal number of doors opened was between 90 and 100, that is to
say, a score supposedly indicating a reward-dominant response style. By
responding persistently in this way, the participant lost all points and
failed to earn a meaningful prize. However there was a large range of
responding, with some participants showing an extremely cautious style,
which gained some points but did not permit them to maximize their
score. Another group of boys behaved in the most adaptive fashion,
continuing until they had earned all the points they could and then
quitting while they were ahead (stopping the task as they began to lose
systematically). There were no significant differences between the
6-year-olds' performance and that of the 7-year-olds.

Effect of the Story (Experimental Manipulation)

To see whether the story had any effect on their performance of the
computer game, an analysis of variance was conducted with number of
doors opened as the dependent variable (see Table 1). To examine the
main effect of conduct difficulties, the participants were divided,
after the fact, into two groups: Typical and Externalising. The latter
category was derived from two criteria: a teacher rating of 3
(occasionally revealing behaviour problems) or greater, and an
Externalising score on the CBCL greater than 60 (the bottom of the
clinical range). This allowed a 2 (story condition) by 2 (typical or
conduct problems) ANOVA to be performed. There were no differences in
the two story conditions (means of 68 and 71), however the main effect
for conduct was significant, with boys in the Typical group opening an
average of 57 doors, and boys in the Externalising group opening 86, F
(1,102) = 32.9, p < .001. There was no significant interaction
between story condition and conduct.

Categorising Participants According to Reward Dominance

A problem with using number of doors opened as the dependent
variable for this task is that these scores do not constitute a linear
scale. A very low score probably indicates something akin to anxiety
(barely persisting with the task and not responding sufficiently to
experience much in the way of point loss); 14 boys performed this way.
An intermediate score indicates adaptive behaviour, and a high score
suggests reward dominance. Using these scoring criteria, 80 boys were
classified as Reward Dominant, and 42 as Adaptive. We then conducted
t-tests to see on which parent of teacher rated variables these two
groups differed. Analysed this way, only one variable significantly
distinguished them: boys categorised as Reward Dominant had higher
scores on the CBCL domain of "withdrawal." High scores on this
dimension indicate little involvement in social activities and/or social
organizations.

Most Serious Conduct Problems

An alternative way of categorising the participants was to combine
CBCL scores and teacher ratings, thus making it possible to identify
those boys who met clinical criteria for conduct disorder. Participants
were categorised this way on the basis of both CBCL scores (clinical
cut-off, T> 70) and the highest level of the teacher ratings. This
yielded a total of 13 boys in what might be called a
"clinical" subgroup, all of whom revealed a strong
reward-dominant style, with 12 of them opening 100 doors (maximum point
loss), and one of them opening 66 doors.

Discussion

In non-clinic referred children, the Miami Door Opening Task
yielded great variability, from those boys who stopped the task almost
immediately without attempting to maximise their gains, to those who
persisted and ended up losing all their previously earned points. A task
that produces such wide-ranging individual differences is potentially
quite a useful measure, but whether it measures previous learning
histories and highly variable decision-making strategies by the
children, or whether it measures an enduring and basic trait of
"reward dominance," is difficult to know. Further work using
tasks of this kind needs to be conducted to better operationalise the
construct of reward dominance.

We did show that for these New Zealand boys, performance on the
task was not influenced simply by providing a general intervention
specifying the value of maximising one's rewards while ahead. The
story read to the children seemed to have high interest value for the
children and was presented immediately before the task. This procedure
represented the sort of cognitive training that might be used clinically
in skill-building approaches for this age group: cognitive therapies
attempt to teach general internalised rules about taking one's
time, looking around, and paying attention to what is being reinforced
in a particular situation (Dodge, 1993; Meichenbaum, 1977).

There are various possible reasons why the intervention did not
influence the boys' behaviour. One is that the cognitive training
simply did not generalise to the computer game, either because the theme
was too different and thus not seen as relevant, or because the
cognitive message for what Fred the Kiwi should have done is not the
same skill as stopping a task when contingencies change. This may be a
limitation of cognitive interventions in general. Some boys commented
that having experienced the task itself they would do better the next
time, and it is likely that direct practice with the task is more
influential than very indirect, vicarious instruction whose relevance
may not be obvious. It is possible that performance on the Miami Door
Opening task is indeed controlled by a response style that serves
essentially like a trait-characteristic to influence performance on many
tasks involving some combination of loss and gain. The interesting
implication of this latter idea is that a self-control strategy
emphasising stopping a behaviour, might be less successful than one that
encourages the boys not to think about the reward, such as devaluing or
trivialising it (a sour grapes strategy), of imagining gaining some
other reward entirely.

Given the variety of sources of individual difference, it is
understandable that there would be only a weak relationship between task
performance and the degree to which others (teachers and parents)judge
the conduct of these children. When the boys were categorised into
adaptive versus reward-dominant groups, the reward-dominant responders
were rated by their parents as "withdrawn," meaning less
involved in social activities, social organizations, and friendships. It
is possible that unpopular boys who do not participate in positive
social groups, experience the deficit reward environment about which we
speculated in the introduction.

On the other hand, classifying children as either Antisocial or
Typical, we did find that the boys considered to have externalising
conduct problems on two ratings, opened more doors and earned fewer
points. It was also possible to look through this large group of school
children for those who met clinical criteria for conduct disorder. We
were able to identify 13 boys with high Externalising scores on the CBCL
and the most extreme teacher ratings of problem behaviour. All these
boys were high scorers on the task, that is, showing the
"reward-dominant style." This finding would seem to replicate
previous research demonstrating that clinic-referred children were
judged to be reward dominant.

More empirical work will need to be done on this particular task,
or others like it, so that the variables influencing performance can be
better understood. Anecdotally, those boys who verbalised self-imposed
rules, such as "if I lose three more points I will quit," were
able to cease responding and maximise their points and thus the value of
their reward Are deficits in such self-regulatory skills part of the
characteristics of children thought to be reward dominant? And what
about the relative importance of the reward (the points and their
related toys) versus the "punishment" or cost of their loss?
The boys generally enjoyed the game; like the one-armed bandit of any
casino, there is entertainment value in the game itself, regardless of
losing the points one had previously earned. In other words, the game
taps considerable individual differences in learning histories,
self-regulation, and personal values assigned to the tangible gains and
losses, and none of these characteristics are easily equatable with
reward dominance as understood in the basic biological mechanisms of the
reward and punishment systems.

In conclusion, there are some theoretically interesting and
plausible links between conduct problems and an emphasis on seeking
reward (rather than avoiding punishment). Children who meet clinical
criteria for conduct problems of ah externalising nature do show a
reward-dominant pattern, but so do many other, typical boys. In New
Zealand, as in the UK and the USA, the Miami Door Opening Task reveals a
widely distributed pattern ofbehaviour, from a maladaptive tendency to
give up early, to perseveration of a previously rewarded behaviour that
is no longer functional. Such variability in behaviour seems worth
exploring further, although it is likely that many factors influence
children's scores on the task. It cannot yet be confirmed that
response style on this task represents a valid and discriminative
measure of the latent construct of reward dominance, nor that reward
dominance will prove to be an enduring trait derived from individual
biological differences.

Acknowledgement

We would like to thank Karma Galyer and Moana Waitoki for their
assistance in conducting this study.